Flammable liquids are very common, especially in our industry, and today we will be covering what are flammable liquids, how and why they can catch fire, the different classifications, and a few examples of highly used industrial flammable liquids.

The flash point of a liquid is the lowest temperature at which the liquid gives off enough vapor to be ignited at the surface of the liquid. Did you catch that? It’s actually the vapor the liquid gives off that burns, not the liquid itself, which is a common misconception.

All flammable liquids fall into four distinct categories (courtesy of OSHA) based on their closed-cup flash point and their boiling point (the temperature at which the liquid starts to boil).

Flammableliquidsexamples

Now that we know all about how flammable liquids are used and where, let’s take a look at some examples of the more widely used industrial-scale flammable liquids.

There are numerous methods of measuring a flash point, but for the most part, the methods are separated into two main categories: open-cup flash points and closed-cup flash points.

Keep in mind that because closed-cup flash points are conducted in a controlled and sealed vessel, the flash point is likely to be at a lower temperature than during an open-cup test.

Source: “Tractor-trailer containing flammable chemical crashes and overturns on I-40 in Greensboro, NC”, Fox News, JUNE 17, 2019, North Carolina

*When a Category 3 liquid with a flash point at or above 100°F (37.8°C) is heated for use to within 30°F (16.7°C) of its flash point, it shall be handled in accordance with the requirements for a Category 3 liquid with a flash point below 100°F (37.8°C).

Let’s say you are a project engineer for a defense contractor in the aerospace industry. You are building a high-tech space shuttle meant to travel extreme distances in space.

In contrast, during a closed-cup flash point test, the vessel is sealed, and the ignition source is actually inside the vessel to closer simulate real-life situations (think of flammable liquid in a drum or fuel tank).

Storage of flammableliquidsRegulations

If you have any of the above flammable liquids in your facilities it is very important that you are aware of them and absolutely follow all of the OSHA and NFPA guidelines for handling, storage, and transportation, not only to remain audit complaint but also for you and your employees’ safety and good health.

Flammableliquidssymbol

For example, ethyl ether has an autoignition temperature of 356°F (160°C) – a temperature that every household oven can reach.

So not only did we create this great downloadable PDF of the chart below as a reference guide, but we also clear up any questions in this post >> Flammable Liquids Classes & Categories.

SOURCE: https://www.nfpa.org/News-and-Research/Data-research-and tools/Hazardous-Materials/Fires-Starting-with-Flammable-Gas-or-Flammable-or-Combustible-Liquid

According to the National Fire Protection Association (NFPA), U.S. municipal fire departments respond to an estimated average of 160,910 fires per year that start due to the ignition of a flammable or combustible liquid; 105,520 (65%) of which started at non-residential properties.

*When a Category 4 flammable liquid is heated for use to within 30°F (16.7°C) of its flash point, it shall be handled in accordance with the requirements for a Category 3 liquid with a flash point at or above 100°F (37.8°C). When liquid with a flash point greater than 199.4°F (93°C) is heated for use to within 30°F (16.7°C) of its flash point, it shall be handled in accordance with the requirements for a Category 4 flammable liquid.

Substances like Xylene have the potential to catch fire in transit – say the fuel tanker was in a highway accident, just like this truck hauling Xylene did in North Carolina on June 17, 2019.

flammable liquid class a b c d

Now that we have covered how we find out if a liquid is flammable, let’s discuss the different flammable liquid classifications and their different flash point ranges.

When bringing up the different flammable liquid classes, we always get the question, “How would they light on fire in the real world”?

FlammableliquidsClass B

FlammableliquidsClass

Autoignition is when a substance reaches a certain temperature at which it self-ignites without any obvious sources of ignition, such as a spark or flame.

It is amazing just how many materials and products go into creating the “final shelf products” that we use every day, and flammable liquids are absolutely one of those production materials.

Flammable liquids are defined by the Occupational Safety and Health Administration (OSHA) as any liquid having a closed-cup flash point at or below 200°F (93°C).

If you are involved in the Aerospace, Semiconductor, R&D, Solar, or Microchip manufacturing industries – chances are you come across flammable liquids on a daily basis.

Most flammableliquidslist

It occurs when flammable liquids are exposed to extremely high temperatures and at that point, no spark is needed for the vapors to catch on fire.

Many of the materials and supplies that go into this project could include fuel, paint, solvents, cleaners, etc. – many of which are flammable liquids. You might need Xylene (a solvent), for example, to regularly clean your equipment.

All content on this website is for informational purposes only. This information should not be considered complete, up to date, and is not intended to be used in place of the consultation or advice of a legal, medical, or any other professional. Chemical Strategies, Inc. assumes no responsibility or liability for any errors or omissions in the content of this site. We do not make any warranties about the completeness, reliability, and accuracy of this information. You use all information at your own risk.

Class 1 flammableliquidslist

Today, we want to focus on flammable liquids on a larger scale and the particular industries that use them on a daily basis.

This list is by no means a complete list of all large-scale flammable liquids, but it does include some of the most commonly used flammable substances.

Note: The National Fire Protection Agency (NFPA) has a very different definition of a flammable liquid and even more different classification system. We break down OSHA and NFPF’s definitions in this post about flammable liquid classes and categories so there is no confusion.

It is also important to know exactly what classes of flammable liquids you have in your facilities as they have different handling and storage procedures.

Think of it this way – in order to auto ignite, it would be like tossing a container of flammable liquid into a giant wildfire – extremely high temperatures and something you would never do intentionally.

The temperature of the substance is raised, and an ignition source is placed over the top of the vessel, waiting for ignition.

Usually, it would take some kind of stimuli for flammable liquids to catch fire whether that be temperature or some kind of spark; however, there is something called “autoignition”.

In order to measure a flash point, scientists in a controlled environment have to introduce an ignition source to the substance, increase the substance’s temperature, and wait for the “flash”.